Heat sink welding and purging apparatus

ABSTRACT

A heat sink welding and purging apparatus for use in the welding of pipe joints for piping to be used with nuclear power systems and the like wherein the weld area must be kept below a temperature at which the dangers of carbide precipitation occur. The various embodiments include expandable heat sink and sealing bladders which are expanded in use to respectively seal the adjacent interiors of the ends of the two pipes to be welded at the adjacent joints. After expanding and sealing the pipe openings, coolant is fed into the interior of the apparatus to cool the joint being welded. Also purging gases may be used to eliminate undesirable atmospheric gases adjacent the weld joint.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to apparatus for use with the weldingof piping to be used in nuclear power plants and systems. It relatesspecifically to the apparatus used for heat sinking and purging of thepiping.

2. Description of the Prior Art

A common problem with known devices used in the welding of pipes is thatthey do not offer the flexibility of both cooling as a heat sinktogether with purging features. Known type devices merely provide heatsink or cooling functions, or purging functions, but not the combinationof same.

Another problem with known type devices are that they are not readilyadaptable for large scale operations or mass welding of numerous piping.That is, they are so complex and involved that much time is spent insetting them up and they are not easily transferable from one set ofpipes to be welded to another set.

Another problem with known type devices is that they are not readilyadaptable for use with either gas type purging functions and/orliquid-type purging and cooling functions.

Known prior art patents which may be pertinent to this invention are asfollows:

U.s. pat. No. 2,470,744 -- May 17, 1949

U.s. pat. No. 2,819,517 -- Jan. 14, 1958

U.s. pat. No. 3,194,466 -- July 13, 1965

U.s. pat. No. 3,431,945 -- Match 11, 1969

U.s. pat. No. 3,779,068 -- Dec. 18, 1973

U.s. pat. No. 3,902,528 -- Sept. 2, 1975

None of these known prior art devices offers the new and unique featuresof the invention disclosed herein.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a combination heat sinkand purging apparatus for use with pipe joint welding of piping to beused with nuclear systems.

Another object of the present invention is to provide apparatus whichoffers the flexibility of either purging an area adjacent a jointbetween two pipes to be welded as well as providing heat sink or coolingfunctions to said area.

A further object of this invention is to provide apparatus which will beeasily and quickly installable in the respective open ends of pipes tobe joined by appropriate welding. It is important that said weld, in thecase of piping to be used with nuclear systems, be held below a giventemperature in order to prevent the dangers of carbide precipitation.This is effected by the apparatus of this invention through the heatsink and cooling function thereof.

A still further object of this invention is to provide expandablebladder structure which will seal the adjacent ends of piping to bejoined and welded, and also will permit the addition of either coolingfluid therethrough for heat sink purposes as well as fluid for purgingpurposes.

The various embodiments disclosed herein of this invention teach anumber of ways of sealing the open ends of piping which are to bejointed together by appropriate welding. The embodiments all have thecommon feature of sealing the internal ends of said piping and all alsohave the feature of permitting cooling fluid to be forced in and allowedout of said apparatus. In addition structure is provided for applyingpurging gas or fluid to the area adjacent the joint being welded fordisplacing any undesired air or other gas therefrom. Also, after theinitial root weld is made, coolant may be fed into the joint area foradditional cooling thereof.

The device of this invention has the advantage of being usable as apurging unit, a heat sink unit, or combination of the two. When usingthe devices of the purge unit, inert gas or air is used to inflate thebladder structure. Bleed means associated with the bladder structurepermit the inflated bladders to be deflated in order to facilitate theirremoval from the pipe after the welding of the pipe joint.

When the apparatus is being used for heat sinking and purging incombination, there are many factors to be considered such as: the pipeschedules, the different configuration of the pipes, the weld deposit,and the heat sink temperature desired. Because of these factors, thecooling liquid used may vary from chilled water to water-glycol mix tocryogenics such as freon or LN₂.

Normally, the apparatus of this invention will be used with pumpingunits offering full flow capability and appropriate controls thereforwhich are capable of variable pressure ranges. One embodiment of thedevice shows the use of pre-shaped coils or blocks which are expandedinto engagement with the pipe interiors by means of the expandablebladder units. When a cryogenic coolant is being used a high qualityinsulating pad normally will be placed between these coils or blocks andthe bladder in order to absorb some of the initial cold shock to thebladders.

Another feature of this invention is that all of the gas and liquidlines are equipped with quick disconnect fittings in order to simplyfythe quick transfer of the pumping and purging apparatus from oneapparatus and pipe set-up to another. This permits the quick and rapidwelding of pipe joints on an assembly line or mass production typebasis. This is very important for usable application on a commercialbasis.

Another very important feature is in the fact that with this combinationapparatus the use of purging gas therewith will have no effect upon thecooling and heat sinking process, that is, the proper cooling of theweld and adjacent area will take place irrespective of whether or notthe system is purged by use of a purging gas. Also, if additionalcooling of the weld area is desired, the use of purge gas may becompletely omitted and additional coolant substituted therefor.

The range of cooling for this apparatus and for the nuclear piping to bejoined by welding is in the minus 50 degree F. range and the expandablebladders of this apparatus are made of silicone rubber which has thecharacteristics and capabilities of operating very satisfactorily withinthis temperature range.

These, together with other objects and advantages which will becomesubsequently apparent, reside in the details of construction andoperation as more fully hereinaftrer described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the basic system for use with thevarious embodiments of this invention.

FIG. 2 is a side elevational view, partly in cross section, of the firstembodiment of this invention.

FIG. 3 is an end view, partly in cross section, taken generally alongline 3--3 of FIG. 2.

FIG. 4 is a side elevational view, partly in cross section, of a secondembodiment of this invention.

FIG. 5 is a perspective view of a third embodiment of this invention.

FIG. 6 is a side elevational view, partly in cross section, of the thirdembodiment.

FIG. 7 is an end view, partly in cross section, taken generally alongline 7--7 of FIG. 6.

FIG. 8 is a side elevational view, partly in cross section, of a fourthembodiment of this invention.

FIG. 9 is an end view, partly in cross section, taken generally alongline 9--9 of FIG. 8.

FIG. 10 is an end view, partly in cross section, taken generally alongline 10--10 of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 of the drawings, indicates by reference numeral 10, the basicheat sink and purging apparatus of this invention as installed at thejoining point 20 of the two ends of pipe 12 for the purpose of weldingsame. Letter A indicates the basic apparatus and the gas and liquidlines are shown as extending to the left of the purging apparatusthrough the exit pipe 12. The line 14 is for the input of coolant froman appropriate coolant compressor as shown, connected by a coolant linethereof 14' and a quick connect/disconnect coupling 16. Similarly, acoolant return line 15 is provided which is connected to the coolantcompressor by return line 15' and another quick connector 16. A purginggas unit is also shown connected to purging line 18 through quickconnect/disconnect member 16 and purge line 18'. Quickconnect/disconnect fittings 16 are provided at the ends of lines 14',15' and 18' so that the cooling compressor unit and the purge gas unitmay be used with a large number of heat sink and purge apparatus for aseries of pipe joints to be welded. Thus saving the cost of multiplecompressor and gas units, and also greatly increasing the efficiency andmass production capabilities of the overall combination.

Looking at FIGS. 2 and 3 which show a first embodiment of thisinvention, the apparatus will now be described in detail. Main tubularsupport members 22 are provided which are mounted in the centralinterior of the pipes 12 and straddling the joint to be welded with discsupport members 26 having clamping brackets 28 with line engagingportions 27 provided thereon Appropriate conventional nuts and bolts 29are used to secure the clamps to the bracket members. A circumferentialring 32 is approporiately fastened to the bracket member 26 and providedwith a resilient mounting hub 34. The purpose of these bracket membersare to support and retain the input and output coolant lines and thepurging line. As described above, the input coolant line 14 which in thedrawings is from the left connects to an input T24 which is a teecoupling. The input line then connects with feed through couplings 21 ineach of the support brackets and then connects with an ell angle inputfeed 24' on the far right of the Figure. Resilient, expandable bladdermembers 30 of silicone rubber or the like are provided about the outercircumference of the main tubular members 22. When the input coolant isapplied to input line 14 and through the T member 24 and L coupling 24'to the interior of said bladders, the coolant which is under pressurewill expand the bladders 30 into firm, positive engagement with theinner portion of the respective pipes 12. Thus expanded, these bladderswill form airtight seals between the joint to be welded and the rest ofthe interior of the pipe. Also, the coolant will function as a heat sinkto absorb the excess heat from the weld as it is being made.

The return coolant arrangement is shown along the bottom portion of FIG.2 and consists of the return coolant line 15, connected to anappropriate tee member 25 and an L member 25' through the feed throughcoupling members 23 in the supports 26. With this arrangement of coolantinput and output, a continuous flow of coolant may be provided, whichalso may be varied as to rate in order to determine and control theamount of heat sink effect at the ends of pipes 12 and the jointtherebetween 20. In some cases, after a root pass is made at the weldjoint, that is, the first initial welding step which seals the contactbetween the pipe ends so that the joint then becomes air and gas tight,coolant may be introduced into the area between the bladders 30 and thejoint. This will provide additional direct cooling of the joint.

However, in most cases a purging gas will be added to this area by meansof the purging input line 18 which connects to a coupling 35 on the leftsupport 26 and in turn is exhausted by another coupling 36 in order toadd and exhaust purge gas such as Argon into said interior. It generallyis not necessary to have a return line for the purging gas because itsprimary effect is to purge or displace any air or combustible fluidwithin the interior area B while the welding is being done. Obviously,when the heat sink bladders 30 are collapsed, the purging gas will becompletely exhausted.

Looking now at FIG. 4 of the drawings, the second embodiment of thisinvention will be described. This may basically be similar to thatdescribed for the internal structure within members 22 of the firstembodiment. This second embodiment basically consists of two solid discs46 having mounted about the outer circumference thereof inflatablebladders 40 which when inflated contact with the internal circumferenceof the pipes 12 along contact area 42. Again, input coolant lines areindicated at 14" feeding to input couplings 44 and 44' in the respectiveheat sink and bladder members 40 with the left disc 46 being providedwith an appropriate feed through 41 for the line 14'" which connects tothe input 44". Coolant return lines are indicated by 15" which are alsoappropriately connected to an outlet coupling 45, and a feed through 43,line 15'" and another outlet coupling 45'. A purge input is indicated at18 which connects to a central feed through member 47 for the purpose ofapplying purge gas to the interior C as indicated. As can be seen, aright side feed through member 47'0 is provided for exhausting the purgegas.

In the operation of this second embodiment, the two inflatable heat sinkand bladder units will be appropriately inserted into the ends of pipes12, close to the joint 20 to be welded, and then the coolant couplingswill be coupled to the coolant compressor and the bladders inflated toform an airtight seal within the pipe ends. The rate of coolant flow maybe adjusted for the desired amount and rate of heat sink effect. Purginggas may then be added or, as mentioned above, additional coolant throughthe input line 18 may be added after the first weld pass is made.

FIGS. 5, 6 and 7 show a third embodiment of this invention. Thisapparatus comprises two inflatable bladder members 50 of silicone rubberor the like, mounted and supported by tubes 50 and 51', which are inturn supported from a central pipe 57 by means of flow through spacerelements 53. The spacer elements 53 will permit fluid to pass betweenthe outer circumference of the pipe 57 and the inner diameter of thetubes 51 and 51', as will be described in detail below. A plurality ofsupport plates 52 are also provided having central apertures thereinwhich closely fit over the tubular members 51 and 51'. Complementary andslightly larger discs 52' are provided within the bladder members perse. These may be best seen in FIG. 6. Appropriate bolts 54 and nuts 56secure the plates to the walls of the bladders 50. The plate 52", on thefar right of the FIG. 6 view, is slightly different from the otherplates in that no central aperture is provided therein. As can be seenin FIG. 6, appropriate welding 55 secures the inner plates 52' to therespective tubular members 51 and 51'. This is for the purpose ofproviding mechanical support to the bladder structures as well as toachieve the fluid tight integrity thereof.

A coolant input line 14 is connected to the screw threaded end of inputpipe 57 for applying the coolant through the center of pipe 57 to thebladder on the right. While in the previous embodiments, the coolant hasbeen set forth as being any desired type such as water, freon, or othertype refrigerants etc. In this embodiment, the coolant would normally bewater because no return line is provided to the coolant pump, and thecoolant is simply exhausted or wasted on the surrounding ground area.After the rightmost bladder 50 is inflated by the coolant underpressure, the overflow will pass through the tubular member 51' betweenthe bladders 50 and then into the leftmost bladder to inflate same. Theoverflow from this bladder, after expansion of same, will be through thetubular member 51 to waste exhaust as already mentioned. Again, thecoolant flowing through both bladders will function as a heat sink forthe ends of the pipes 12 and weld joint 20.

After the bladders have been inflated purging gas may also be applied bymeans of the purge lines 18 and 18' connected to the feed throughmembers 60 provided in the support plates 52 and 52' of the leftmostbladder. These feed through members 60 are appropriately screw threadedon the oustide circumference thereof for engagement with center tappedapertures 63 provided in the plates 52' and secured on the outside ofplates 52 by means of locking nuts 61. Connecting lines 68 and 68' areprovided within the bladder to connect the respective feed throughmembers. Thus, as can readily be visualized, when input purging fluid isapplied through line 18 to the feed through coupling 60, the appropriatefluid will be conveyed into the interior between the bladders and theinside portion of the pipe joint 20. An inert gas such as Argon may beapplied through the input line 18 or as already mentioned coolant mayalso be fed therethrough. The lower input 18 feeds the purging gas orcoolant into the device while the upper line 18' is used to exhaustsame.

The forth embodiment shown in FIGS. 8, 9 and 10 will now be described.This embodiment basically comprises units 70 and 70' which are actuallyquite similar in construction. Mounted at one end of each of theseunits, as shown in FIG. 8, are inflatable bladder members 30' similar tothat already discussed with the embodiment of FIG. 2. These bladders 30'are connected by an inflation input line 72 to a T connection 82, and bycontinuing inflation line 72' to the L member 82'. Exhaust or deflationline 73 is provided which is appropriately connected to the T member 83and further by means of deflation or exhaust line 73' to the L 83'. Theinflation and deflation procedure is like that already described above.While normally these bladders would be inflated merely for positioningand blocking purposes, coolant could also be used as the inflation meansand to provide additional cooling to the pipe structure.

Spaced along the members 70 and 70' and toward the other ends of saidmembers from the bladders 30' are smaller inflatable sealing and coolingbladders 40'. These bladders are somewhat similar to the bladders 40described in the embodiment of FIG. 4. However, mounted upon the outersurface circumferentially thereof are metal coolant coils 76 which arefor the purpose of cooling and heat sinking the pipe ends at extremelylow temperatures by cryogenic cooling. Cryogenic cooling functions atextremely low temperatures and the cooling coil 76 and appropriate feedand exhaust lines therefor must be resistant to this extremely lowtemperature and be both extremely strong and flexible at lowtemperatures. The input coolant line is shown at the left of FIG. 8 as74 feeding to the fluid coil 76 of the member 70. An exhaust for thiscoolant is indicated by reference numeral 75. The coolant input for theright member 70' is indicated by line 74' while the exhaust therefor isindicated by the line 75'. Of course the cryogenic cooling is fed byappropriate extremely low temperature pumps, etc., not shown, similar,however, to the coolant compressor shown in FIG. 1. The input line forthe inflating/coolant of the bladder 40' is indicated by referencenumeral 94 connecting to a T92 and then connected by further line 94' tothe L92', and the exhaust for the inflation/coolant of the bladders 40'is by L93', coupling line 95', T93 and exhaust line 95. Thus, as hasalready been described in the previous embodiments, appropriateinflation of the bladders 40' are effected by applying inflation/coolantto the input 94 and controlled by the rate of exhaust through the outlet95. Since the cryogenic method of cooling is such a shock to theassociated components, an appropriate insulator block or layer may beprovided between the outer surface of the bladders 40' and the innersurface of the coolant coil 76 as indicated by the reference numeral 98.Discs 46' having appropriate mounting and clamping structures for therespective lines and support structure, like that for discs 46 of FIG. 4are also provided for this embodiment as shown in the Figures. However,for the sake of clarity reference numerals have not applied to thesesupports and clamps since numerous variations of same may be actuallyutilized and practiced and are basically immaterial to the overallsuccessful operation of the apparatus. The main requirement being thatthey be gas and liquid tight so that purging fluid and/or coolant may beadded to space C.

While the purging input and output lines have not been shown in theseFigures in complete detail, again for the sake of clarity, the lineswould be fed in through one portion of the devices, such as the centerthereof, as generally indicated by the reference numeral 100 in FIG. 8.Again, the purging operation and functions would be as described abovefor the previous embodiments.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:
 1. Apparatus for heat sinking andpurging pipes to be welded for use in nuclear systems and the like,comprising: first means for sealing internally the adjacent ends of twoabutting pipes to be welded; and, second means for directing a coolantinto the first means for cooling said sealed abutting pipe ends in orderto effect a heat sink function in order to keep the temperature of theweld area below that where the dangers of carbide precipitation occur.2. The structure as set forth in claim 1, wherein the first meansincludes inflatable members mountable internally of each of said pipesand expandable by the coolant in order to form a tight seal internallytherewith.
 3. The structure as set forth in claim 2, wherein the secondmeans includes coolant feed lines and coolant return lines associatedwith the inflatable members in order to cool the pipes adjacent thejoint to be welded.
 4. The structure as set forth in claim 3, togetherwith third means for purging the atmosphere in the sealed portionbetween the inflatable members which is internally of the joint beingwelded.
 5. The structure as set forth in claim 3, together with acoolant compressor connected to the coolant feed lines by quickconnect/disconnect couplings, and purge gas source means connected tothe space between the inflatable members.
 6. The structure as set forthin claim 5, wherein the first means also includes central supportstructure for supporting the inflatable members thereon and theassociated lines therefor, and also the input for the purging means. 7.A purging and cooling apparatus for use with the welding of cylindricalmembers, comprising: inflatable means for expandable engagement with thecylindrical members to be welded adjacent the weld joint, and means foradding inflation and coolant medium to the inflatable means forinflating the inflatable means and cooling the area near the weld joint,the inflation and coolant medium being the same fluid material.
 8. Thestructure as set forth in claim 7, wherein the inflatable means includesat least two expandable bladder members which when inflated securelyengage with the metal surface of the cylindrical members, and at leastone inflation-coolant line is provided to each of the bladder members.9. The structure as set forth in claim 8, wherein at least oneexhaust-coolant line is provided to each of the bladder members.
 10. Thestructure as set forth in claim 8, together with separate cryogeniccoils provided on the bladder members for contact with the metal surfaceof the cylindrical members, and appropriate input and output linesconnected to said coils for feeding a cryogenic medium through thecoils.
 11. The structure as set forth in claim 9, together with apurging fluid input means for the space between the two inflatablebladder members in order to purge the atmosphere contained between sameand adjacent the weld joint.
 12. The structure as set forth in claim 9,wherein the expandable bladder members are each mounted on a centraltubular support member and the inflation/coolant lines run inside thecentral tubular member for ease of installation and operation.
 13. Thestructure as set forth in claim 12, wherein the exhaust/coolant linesalso run inside the central tubular member for protection and ease ofinstallation in operation.
 14. The structure as set forth in claim 13,wherein the means connected to the inflatable means in order to providethe inflation and coolant medium consists of quick change connect anddisconnect couplings between the inflation/coolant lines and theexhaust/coolant lines in order to allow a number of multiple apparatusto be operated from the same coolant compressor.
 15. The structure asset forth in claim 12, together with separate purge gas means forapplying an inert gas to the area between the two inflated bladdermembers and the weld joint for the purpose of displacing any combustibleand contaminated air contained therein.
 16. The structure as set forthin claim 15, wherein the purge means includes a separate purge line runinside of the central tubular member and supported thereby, and purgegas supply means connected to the external portion of said purge line byquick connect/disconnect coupling.
 17. The structure as set forth inclaim 15, wherein the purge means includes a separate purge line runthrough one of the bladder members and opening into the weld area, andconnected to a source of purge gas by quick connect/disconnect couplingmembers externally of the pipe end bladder member.
 18. The structure asset forth in claim 9, wherein the expandable bladder members each have acentral tubular support member, and the inflation/coolant lines runinside the central tubular support members for ease of installation andoperation.
 19. The structure as set forth in claim 18, wherein theexhaust/coolant lines also run inside the tubular support members forprotection and ease of installation and operation.
 20. The structure asset forth in claim 19, wherein the means connected to the inflatablemeans in order to provide the inflation and coolant medium consist ofquick change connect and disconnect couplings between theinflation/coolant lines and the exhaust/coolant lines in order to allowa multiple number of apparatus to be operated from the same coolantcompressor.
 21. The structure as set forth in claim 18, together withseparate purge gas means for applying an inert gas to the area betweenthe two inflated bladder members and the well joint for the purpose ofdisplacing any combustible and contaminated air contained therein. 22.The structure as set forth in claim 21, wherein the purge means includesa separate purge line run inside at least one of the tubular supportmembers and supported by same, and purge gas supply means connected tothe external portion of said purge line by a quick connect/disconnectcoupling.